Medium duty, wear resistant machine element



United States Patent 3,198,631 MEDIUM DUTY, WEAR RESISTANT MACHKNE ELEMENT Dougles E. Jones, 1716 7th St. Menominee, Mich. No Drawing. Filed May 1, 1961, Ser. No. 106,459 2 Claims. (Cl. 75-128) This invention relates to inexpensive, wear resistant elements formed of iron-base, non-magnetic alloys rich in chromium and nickel the structure of which is one of complex carbides in an austenitic matrix, arranged or oriented in the normal dentritic, as cast, form. The elements may be in the forms of valves, valve seat inserts, and other machine elements for use in medium duty applications wherein the elements must retain their hot hardness, resistance to wear, and corroison resistance, at elevated temperatures. The invention also relates to the compositions from which such machine elements may be formed.

One of the main objects of the invention is the provision of inexpensive medium duty, wear resistant machine elements, such as hard faced or surfaced valves and valve inserts, which may be used in medium duty applications wherein they must be able to withstand medium severe operating temperatures, pressures and corrosive atmospheres without losing their hardness.

Another important object of the invention is the provision of inexpensive alloys for making such medium duty, wear resistant elements which may be used in the as cast condition Without heat treatment and have a hardness within the range of about 35 to 45 on the Rockwell C scale.

Certain other objects of the invention will be apparent from the following more detailed description and the appended claims.

The machine elements of this invention may be formed of alloys falling within the following general composition:

Percent by weight Iron 45.0-73.0

Chromium 12.0-17.0 Nickel 12.0-170 Silicon 1.5-4.0

Molybdenum 0.0-5.0 Tungsten 0.0-5.0 Manganese 0.5-2.0 Vanadium 0.0-2.5 Carbon 1.0-2.5

Alloys from which machine elements may be made having excellent properties according to this invention have the following preferred composition:

Percent by weight Alloys of the foregoing preferred analysis have been used to make valves and valve inserts for all types of internal combustion engines. These alloys may also be used to make other machine elements which must exhibit good wear resistance under moderately severe operating conditions.

3,i98,03l Patented Aug. 3, i965 "ice The three following formulations falling within the general composition set forth above have the special properties indicated by their respective headings:

MAXIMUM HOT HARDNESS Chromium 15.25-16.00 Nickel 13.50-14.25 Silicon 2.50-2.75 O Molybdenum 0.75-1.00 Manganese 0.60-0.70 Carbon 1.90-2.00 Iron Balance MAXIMUM HOT STRENGTH Chromium 12.00-12.75 Nickel 13.50-14.25 Silicon 2.50-2.75 Molybdenum 1.75-2.25 Tungsten 1.75-2.25 Manganese 0.75-1.00 Carbon 1.90-2.10 Iron Balance MAXIMUM DUCTILITY Chromium 14.00-14.75

Nickel 14.25-15.00

Silicon 2.50-2.75 Tungsten 1 maximum Molybdenum 1 maximum Manganese 0.50-0.70 Carbon 1.10-1.30

iron Balance The following specific example will serve to further illustrate how this invention may be practiced.

Example I The following is typical of a production heat of approximately 200 lbs.

Melt formula: Lbs.

Nickel metal 28.80 11.? pig iron 90.00 Mild steel scrap 3 0.00 Low carbon ferrochrome (72% Cr.) "43.60 Ferrosilicon (83% Si) 3.90 Ferromanganese (83% mn.) .50 Ferromolybdenum (62% Mo.) 2.75 Carbon .32

(A) Elements and alloys may be melted in any suitable melting device, although induction melting lends itself to better control. Special techniques such as the use of inert atmospheres (i.e. argon) or vacuum may be beneficial but are not generally necessary. Standard deoxidization practices (i.e. ferr-osilicon, calcium silicon, etc.) are normally beneficial.

(B) This alloy may be cast into almost any type mold material although best results will be obtained with dry molds (i.e. shell molds, fired ceramic molds, etc.)

(C) Pouring temperatures will be determined by the complexity of the casting to be produced, its section size or sizes, and mass. Temperatures 250 to 500 degrees F. above the melting point prove most satisfactory. The lower tern erature intended for preheated molds or fairly heavy castings and the higher temperature for small castings of thin section in room temperature molds. Melting point of the alloy is approximately 2365 degrees F. more or less depending on composition within the specification.

(D) The above melt formula will produce castings having a composition approximately as follows:

Chromium 15.50

Nickel 14.40

Silicon 2.38 Molybdenum .82 Manganese .58 Carbon 1.90

(E) Some elements will vary from the composition indicated by an amount dependent on type of melting unit employed, temperatures used, and time consumed in melting, and in some cases the refractory material used for furnace lining.

(F) It should be recognized that the materials used in the melt formula are one combination of many that are possible and permissible (i.e. careful use of secondary metals and analyzed scrap).

What is claimed as new is:

1. A wearresistant valve member for an internal combustion engine formed of an alloy having the following composition:

Chromium 15.25-16.00

Nickel 13.50-14.25

Silicon 2.50-2.75

Molybdenum 0.75-1.00

Manganese 0.60-0.70 Carbon 1.90-2.00

Tron Balance 2. A wear resistant valve member for an internal combustion engine formed of an alloy having the following composition:

FOREIGN PATENTS 545,377 8/57 Canada.

DAVID L. RECK, Primary Examiner.

MARCUS U. LYONS, RAY K. WINDHAM, Examiners. 

1. A WEAR RESISTANT VALVE MEMBER FOR AN INTERNAL COMBUSTION ENGINE FORMED OF AN ALLOY HAVING THE FOLLOWING COMPOSITION: 